- turning error
- turret
- twilight orbit
- twisted pair
- twisted together
- typing position
- UHF band
- ultrasonic vibration
- umbilical tower
- umbrella antenna
- unamplified circuit
- underbunching
- twin paradox
- UHF signal
- ullage rocket
- unavailable
- unblanking
- uncommitted transistor
- uncut length
- undefined record
- underground antenna
- underflown exception
- underground chamber
- underground line
- underwater antenna
- underwater propagation
- undulating surface
- unencumbered balance
- unfurlable antenna
- unhook
- unidirectional antenna
- uniform function
- undershoot
- undissociated dislocation
- undistorted
- unfired tube
- unforeseen interruptions
- unfurlable aerial
- unicode
- union rule
- unipolar IC
- unique record
- unit line
- unijunction transistor
- unit motor
- unit voltage
- universal coil
- universal number
- university
- unloaded cable
- unlock
- unsatisfactory services
- unpacking
- unmanned exchange
- unspent balance
- up state
- updating rate
- uplink
- urban network
- usable envelope
- used
- useful effect
- unused
- up time
- up-converter
- upper ionosphere
- update right
- uplink block
- urgent message
- user agent
- user directory
- user identification
- user label
- user library
- user-key
- user-port
- utility device
- utility satellite
- v antenna
- vacancy
- vacuum diode
- vacuum phototube
- vacuum triode
- validity
- vapour deposition
- varactor chip
- varactor turning
- variable persistence
- variable attenuation
- variable point
- vector field
- vector operator
- vector scanning
- vee antenna
- vehicle fleet
- velocity increment
- velocity measurement
- velocity navigation
- vernal point
- vernier engine